The present invention relates to drive systems for bicycles or other operator powered, wheeled vehicles, and in particular to a system for converting a bicycle having at least one spoked wheel to enable motor propulsion or assist therefore.
The preferred embodiment of the present invention teaches a spoke mounted, pulley/belt drive wherein there is provided a drive hub configured to quickly, easily, and safely mount to the spokes of an off-the-shelf spoked wheel on a vehicle such as, for example, a bicycle, so as to allow said wheel to be driven by a motor mounted to the frame of the bicycle.
With the hub of the present invention, no special tools or measurements are required for mounting the unit. The hub has an outer face having formed therein a channel or belt track for engaging a drive belt from the motor; the inner side of the hub has formed therein spoke slots configured to accept and lock upon spokes situated on the front or rear wheel of the bicycle, which slots are situated such that the hub is self-centering upon installation, namely, when all of the slots are lined up to engage spokes on the bicycle, the hub is appropriately centered on said wheel. Each spoke slot is of a width so as to accept the spoke, with there being provided ridges, notches or the like for engaging and locking about the spoke to resist removal of the hub from the wheel, once mounted thereupon.
The hub is driven by a small motor (electric or gasoline) mounted to the frame of the unit, via a friction belt drive system. The motor may be situated upon a small motor mount which is in turn bolted to the frame. The motor may be controlled by the operator via a throttle which may be situated at the handlebars and which relays the control to the motor via a throttle cable.
The system of the present invention is configured to be installed without special tools by a novice, and is designed to require no special skills for operation, installation, or maintenance.
The prior art is replete with patents teaching various systems for motorizing bicycles and the like, wherein there is provided an internal combustion or electric motor mounted to the frame, and various drive means for linking the motor to a wheel of the vehicle. It is this linkage means which has been a weak link in prior designs in converting a user operated vehicle to a motor assist vehicle. As will be shown below, prior art linkages have include friction drives which directly engaged the tread of the wheel, as well as specialized hubs or wheels which were either complicated installation, expensive or limited in their compatibility with off-the-shelf bicycles, or unreliable in their use.
Some patents illustrating prior art systems include:
Japan 291175 Nov. 7, 1996
Japan 329873 Dec. 19, 1996
U.S. Pat. No. 6,024,186 issued 2000 teaches an xe2x80x9cAuxiliary Power Supply Apparatus For Bicyclesxe2x80x9d teaching a drive hub affixed to the spokes via bolts. It would appear that the hub must be somehow aligned such that the axle is centered to optimize operation of the system.
U.S. Pat. No. 3,966,007 teaches an xe2x80x9cElectricbikexe2x80x9d wherein there is utilized a friction wheel (122) which engages the treads of the rear wheel of the vehicle.
U.S. Pat. Nos. 2,575,873 and 731,207 teaches a motorized vehicles, each comprising a motor mounted to a bicycle frame, and drive means comprising a sprocket mounted to the axle of the rear wheel.
U.S. Pat. No. 5,341,892 teaches a vehicle having an enclosed hub which encases a motor (10) mounted about the axle.
U.S. Pat. No. 5,507,512 teaches a circular weight, configured to function as a flywheel, which is fastened to the spokes via a clip.
U.S. Pat. No. 4,836,615 teaches a disc cover which is affixed to the wheel via clip means having a slot which permits the spoke to be slipped therethrough.
U.S. Pat. No. 3,912,039 for a bicycle drive apparatus including a drive plate which xe2x80x9cis clamped to the wheel spokes by suitable clamping devicesxe2x80x9d. As indicated: xe2x80x9cA split clamping ring 16 is then positioned adjacent the interior edges of the spokes and suitable fastening screws are used to bolt the clamping ring 16 to drive plate 15 with the wheel spokes intermediate the clamping ring and the drive plate.xe2x80x9d A friction wheel from a motor directly engages the drive plate to drive the rear wheel of the cycle.
U.S. Pat. No. 1,410,180 teaches a xe2x80x9cmotor cyclexe2x80x9d wherein there is provided a drive hub (h) mounted to the rear wheel of the vehicle, but no mention appears to be made as to how the hub is affixed to the wheel, if it is affixed to spokes (spokes are not shown), or if it is part of a custom wheel fabrication.
U.S. Pat. No. 5,893,614 teaches a wheel covers which are screwed in place about the spokes hear the hub of the wheel.
Japanese Patents 329873 and 291175 would appear to teach a motorizing kit for a bicycle, utilizing a drive hub, U.S. Pat. No. 291175 apparently illustrating (FIG. 2) the hub apparently mounted to the spoke (FIG. 6) via a back plate (29) and screws (27). This hub would prove more difficult to install than the present invention, requiring not only additional time and the use of screws as fasteners (which could come loose and fall out when affixed to a vibrating spoke), but would appear also to require manual centering of the hub on the wheel, as well as different size hubs for different size wheels.
In summary, there would appear to be being literally dozens of patents teaching gas operated or electrical motor kits designed to interface in one manner or another with a wheel of a bicycle to drive same. Past methods have included friction wheels or rollers configured to directly engage the tread of the bicycle tire, as well as specialized hubs which replaced one of the tires. Nonetheless, the prior art would appear to have failed to have contemplated or suggested an easily mounted drive hub designed to interface with an off-the-shelf spoked wheel on a bicycle, which is inexpensive in manufacture, quickly and securely mounted to the wheel without special tools or measurements, and compatible with different sized wheels.
Unlike the prior art, the present invention provides an aftermarket motorized assist system for bicycles or the like which is easily installed by a novice, reliable in operation, inexpensive to purchase and maintain, and safe and easy to operate.
The preferred embodiment of the present invention contemplates a spoke mounted, pulley/belt assist drive system for a bicycle or the like, comprising a wheel pulley adopted to universally interface with the spokes of a bicycle wheel, the wheel pulley forming a drive hub, alternatively called a drive ring, for receiving a drive belt from a motor mounted to the frame of the bike. The drive hub has formed therethrough slots formed along a side wall, said slots configured to engage the spokes on the bike for the purpose of retaining the pulley in place on the wheel, so that the hub may be driven via a drive belt communicating with a motor mounted to the frame of the vehicle.
A belt track is formed along the outer peripheral wall of the pulley for receiving the drive belt. The belt is tensioned via a counter pulley/tension spring arrangement.
Unlike the prior art, the drive hub of the present system is quickly and easily mounted to the drive wheel of the bicycle or the like, the drive hub configured to engage spokes in forming the support for the drive wheel by securely snapping about same via spoke slots formed along an edge of the hub. The spoke slits have further formed therein ridges, notches, or the like to enable the spokes to be removably locked into place in their respective slots.
In installation, no separate step of centering is required because lining up the slots on the hub with each of the spokes effectively centers the hub as it is being installed, without tools or measurements. In contrast, other prior art systems generally required specialized tools, equipment, or training, or a custom designed vehicle for receiving the drive/assist unit.
Most bicycle wheels have 36 spokes, 18 spokes emanating from each opposing side of the axle; this arrangement is common on 24xe2x80x3, 26xe2x80x3 and 27xe2x80x3 wheels. With the drive hub of the present invention, it may not be necessary that the hub engage each of the 18 spokes forming one side of the wheel. The drive hub can in fact have nine spoke slots formed so as to engage nine spokes on the wheel, and this will allow the same hub to fit different sized wheels.
It is therefore an object of the present invention to provide a drive hub which is inexpensive to manufacture and easy to install.
It is another object of the present invention to provide a drive hub which has formed therein spoke slots of a geometry and configuration so as to securely and effectively engage off-the-shelf spoked wheels of a bicycle or the like.
It is another object of the present invention to provide a motorized drive system for bicycles or the like which may be installed by a novice, and which is safe in operation.
It is another object of the present invention to provide a motorized drive system which is inexpensive in manufacture and reliable in operation.
Lastly, it is an object of the present invention to provide a method and system for converting a bicycle to provide motorized assist which is easy to operate, install, and maintain.